Process for reducing color of a polyglycerol

Abstract

The present invention relates to a process for reducing color of a polyglycerol. The process includes the steps of treating said polyglycerol with a first bleaching agent such as bleaching earth and treating said treated polyglycerol with a second bleaching agent such as hydrogen peroxide.

The invention claimed is: 
     
       1. A process for reducing color of a polyglycerol, the process comprising:
 (a) treating said polyglycerol in an aqueous medium containing water with bleaching earth, wherein said bleaching earth is added to said aqueous medium at a concentration of 10% to 50% based on the weight of said polyglycerol; 
 (b) removing said bleaching earth from said treated polyglycerol; 
 (c) drying said treated polyglycerol from which said bleaching earth was removed to remove excess water; and 
 (d) further bleaching said dried polyglycerol with hydrogen peroxide while heating. 
 
     
     
       2. The process as claimed in  claim 1 , wherein said polyglycerol is obtained by heating glycerol monomers with a catalyst using microwave irradiation. 
     
     
       3. The process as claimed in  claim 1 , wherein the polyglycerol is obtained by heating glycerol using microwave irradiation. 
     
     
       4. The process as claimed in  claim 1 , wherein said polyglycerol is obtained by reacting a glycerol in the presence of a catalyst at a temperature from 200° C. to 310° C. for 30 minutes by microwave irradiation. 
     
     
       5. The process as claimed in  claim 4 , wherein said catalyst is selected from potassium acetate, sodium acetate anhydrous, sodium acetate trihydrate, sodium formate, tri-sodium citrate, or potassium citrate. 
     
     
       6. The process as claimed in  claim 5 , wherein said catalyst is added in an amount of 0.5 to 10 weight percent to the weight of said glycerol. 
     
     
       7. The process as claimed in  claim 1 , wherein said bleaching earth is added to said polyglycerol at a concentration of 50% based on the weight of said polyglycerol. 
     
     
       8. The process as claimed in  claim 7 , wherein a mixture of said bleaching earth and said polyglycerol is heated at a reaction temperature of 50° C. to 60° C. 
     
     
       9. The process as claimed in  claim 8 , wherein said mixture is stirred at 600 rpm for a duration of 30 minutes. 
     
     
       10. The process as claimed in  claim 9 , wherein said mixture is filtered after said stifling to recover said treated polyglycerol from said bleaching earth. 
     
     
       11. The process as claimed in  claim 10 , wherein said further bleached polyglycerol is dried to remove excess water after being further bleached with hydrogen peroxide. 
     
     
       12. The process as claimed in  claim 1 , wherein said hydrogen peroxide has a concentration of 50% before being added to said treated polyglycerol. 
     
     
       13. The process as claimed in  claim 12 , wherein said hydrogen peroxide is added at concentration of 10% based on the weight of polyglycerol. 
     
     
       14. The process as claimed in  claim 13 , wherein said treated polyglycerol and said hydrogen peroxide are heated at reaction temperature 50° C. to 60° C. 
     
     
       15. The process as claimed in  claim 14 , wherein said treated polyglycerol and said hydrogen peroxide is stirred at 600 rpm for a duration of 15 minutes. 
     
     
       16. The process as claimed in  claim 15 , wherein a final treated polyglycerol is dried to remove the excess water. 
     
     
       17. The process as claimed in  claim 1 , said further bleached polyglycerol having a color scale of 0.8R or less. 
     
     
       18. The process as claimed in  claim 1 , wherein the polyglycerol is obtained by reacting a glycerol in the presence of a catalyst at a temperature from 250° C. to 270° C. 
     
     
       19. A process for reducing color of a polyglycerol, the process comprising:
 (a) treating said polyglycerol in an aqueous medium with bleaching earth while heating to a temperature of 50° C. to 60° C., wherein said bleaching earth is added to said aqueous medium at a concentration of 10% to 50% based on the weight of said polyglycerol; 
 (b) removing said bleaching earth from said treated polyglycerol; 
 (c) drying said treated polyglycerol to remove excess water; and 
 (d) further bleaching said treated polyglycerol with hydrogen peroxide while heating to a temperature of 50° C. to 60° C. to yield polyglycerol with reduced color, wherein the polyglycerol of reduced color has a color scale of about 0.8R or less. 
 
     
     
       20. A process for reducing color of a polyglycerol, the process comprising:
 (a) providing a polyglycerol obtained by reacting glycerol in the presence of a catalyst selected from potassium acetate, sodium acetate anhydrous, sodium acetate trihydrate, sodium formate, tri-sodium citrate, or potassium citrate and added in an amount of 0.5% to 10% by weight of said glycerol, said glycerol being reacted at a temperature from 200° C. to 310° C. by microwave irradiation; 
 (b) treating said polyglycerol in an aqueous medium with bleaching earth, wherein said bleaching earth is added to said aqueous medium at a concentration of 10% to 50% based on the weight of said polyglycerol; 
 (c) removing said bleaching earth from said treated polyglycerol; 
 (d) drying the said polyglycerol to remove excess water; 
 (e) further bleaching said dried treated polyglycerol while heating with hydrogen peroxide; and 
 (f) drying said further bleached polyglycerol to remove excess water.